obtaining the maximum values from the series

I have two series of readings (time, x) and (time, y). Both graphs have cyclic nature which respect to time. With peak and trough in random and different time interval. I want to find the the lag between maximum x and maximum y (each peaks) from the series and plot it against time. Can you help with that?

Answer 1

[Sean de Wolski]

doc findpeaks

http://www.mathworks.com/help/releases/R2013a/signal/ref/findpeaks.html

The problem with looking for the derivative to be zero is that this will almost never happen with real data unless you are saturating to some level. Instead, look for where the derivative changes sign()

[Ede gerlderlands]

Yes, I have used this function but couldn't left out the local maximums from the series . Is there any way of avoiding them ?

[Sean de Wolski]

Use the threshold option. Or find all of the peaks and then pick the best ones from that.

Answer 2

[Image Analyst]

Like I said in your duplicate question, if you want all the local peaks left out, then just use max() -- this will find the one global max.